modern body work/fairings

[dannc29]

hi, just wondering if anyone has tested if there's any speed difference between std cbr400rr fairings and say fairings fitted from a late model bike? just been doing some thinking and from what some manufactures have said i think there may be a top speed increase from just the front mudguard. the std mudguard looks very outdated compared to new guards. any help would be appreciated.

[CMSMJ1]

I doubt it very much. you need brute power for top speed. I seem to recall readoing that the NC30 had one of the lowest ever drag coefficients for a motorcycle and the blackbird too was very low.

you'd get better results making sure you tucked in better

[dannc29]

i seemed to think that aswell, but iv'e found out recently that ktm gained an extra 10km/h in top speed from a front mudguard re-design on there rc8 which i though was outragous at first. but iv'e asked around a few people in the know and apparently some old land speed record bikes got good improvement from better mudguards. and while the old 400rr isn't going to set any land speed records i thought it wouldn't hurt asking if its been done.

anyone else have any good advice?

[yeurman]

I'll let you know after the Manx if i'm any quicker down the Sulby Straight with the new Tyga fairings and mud guard this year. Col

[leopard_pagan]

"you'd get better results making sure you tucked in better"
> or lost some weight.. less load for the bike to pull... lol

[yeurman]

Is this tucked in enough? .. pic taken of me at the Scarborough Road races this year... :)
http://diddley.smugmug.com/gallery/8892 ... 1477_YexbX" onclick="window.open(this.href);return false;
Col

[Cammo]

but iv'e found out recently that ktm gained an extra 10km/h in top speed from a front mudguard re-design

The ffront mudguard is one of the most un-aerodynamic parts of most bikes.

The ultimate setup is to have the front wheel completely shrouded by a guard, but this is illegal in most forms of racing. So are the old 'dustbin' cigar shaped fairings which numerous world speed records were set along with good race results frm increased speed.

Take a look at the front guard of a blackbird and you can see that it's a lot more aerodynamic than most (at the expense of being ugly!). The new hayabusa is another good example, lots of the aerodynamic gain is had by allowing the air to not detach rear of the rider, i.e. it breaks off from the bike more cleanly at the tail.

Aerodynamic effciencies really only come into play at high speeds, but every bit helps at all speeds.


John Robinson's book 4-Stroke Motorcycle Tuning has a good section on aerodynamics. I'll try and get some scans of the chapter if anyone's interested.

[dickdastardly]

I'd be very interested. Be a good little read.

[stimpy]

dude,its a OLD cbr400 that your racing...buy a zxr/fzr400SP to tune,or a 600 or a 1000 if u want to go real fast
i say this because most of the lap records for the 400's here are set by a zxr400 with std bodywork
if anything...maybe try zxr bodywork on the cbr
no offence
stimpy
p.s,KTM changed more than just the front mudguard

[dannc29]

hahaha, stimpy...your yet to witness the sheer power of the nc29. wait till PI. we need to organise a speed gun/trap down there. expect low 45's. a zxr is a better bike to start from but iv'e come this far now so there's no turning back.